Thought it was a sash buckle...

[romeo-1]

...but now I'm not so sure. Found this at a site that has produced everything from the 1600 and up. It is very solid, not presses brass and has two hooks on the back clips as seen in the pictures. Any ideas?

 

[Montana Jim]

You are right... not sash, but a belt buckle face... similar piece shown below.

From this source: 1930's Victorian Dunn Brothers Sterling Silver Belt Buckle from kingdavidstreasures on Ruby Lane

 

[romeo-1]

Looks like you got it Montana...wish mine was silver like the one you posted.